Conductive webs

ABSTRACT

Conductive nonwoven webs are disclosed. The nonwoven webs contain pulp fibers combined with conductive fibers. In one embodiment, the webs are made in a wetlaid tissue making process.

BACKGROUND

Absorbent articles such as diapers, training pants, incontinenceproducts, feminine hygiene products, swim undergarments, and the likeconventionally include a liquid permeable body-side liner, a liquidimpermeable outer cover, and an absorbent core. The absorbent core istypically located in between the outer cover and the liner for taking inand retaining liquids (e.g., urine) exuded by the wearer.

The absorbent core can be made of, for instance, superabsorbentparticles. Many absorbent articles, especially those sold under thetradename HUGGIES™ by the Kimberly-Clark Corporation, are so efficientat absorbing liquids that it is sometimes difficult to tell whether ornot the absorbent article has been insulted with a body fluid.

Accordingly, various types of moisture or wetness indicators have beensuggested for use in absorbent articles. The wetness indicators mayinclude alarm devices that are designed to assist parents or attendantsidentify a wet diaper condition early on. The devices can produce anaudible signal.

In the past, for instance, wetness indicators have included an opencircuit incorporated into the absorbent article that is attached to apower supply and an alarm device. When a conductive substance, such asurine, is detected in the absorbent article, the open circuit becomesclosed causing the alarm device to activate. The open circuit maycomprise, for instance, two conductive elements that may be made from ametal wire or foil.

Problems have been experienced, however, in efficiently and reliabilityincorporating wetness indicators into absorbent articles at the processspeeds at which absorbent articles are produced. Thus, a need exists forimproved wetness sensors that can be easily incorporated into absorbentarticles.

In addition, a need also exists for conductive elements for use in awetness indicator that are made from non-metallic materials.Incorporating metallic components into an absorbent article, forinstance, may cause various problems. For instance, once the absorbentarticles are packaged, the absorbent articles are typically exposed to ametal detector to ensure that no metallic contaminants have accidentallybeen included in the package. Making the conductive elements of awetness indicator from a metal, however, may cause a metal detector toindicate a false positive. The incorporation of metal conductiveelements into an absorbent article may also cause problems when thewearer is attempting to pass through a security gate that also includesa metal detector.

SUMMARY

The present disclosure is generally directed to a conductive nonwovenweb that may be used in numerous applications. For example, in oneembodiment, the nonwoven web may be used to form conductive elements ofa wetness sensing device incorporated into an absorbent article. In oneembodiment, the conductive nonwoven web contains a substantial amount ofpulp fibers combined with conductive fibers and is formed through atissue making process. The resulting web, which may have many similarproperties to a tissue web, can then be easily incorporated into anabsorbent article during its manufacture for forming an open circuitwithin the article. For example, in one embodiment, two strips or zonesof the conductive nonwoven web are incorporated into an absorbentarticle for forming an open circuit. When a conductive substance extendsbetween the two strips or conductive zones, a signaling device may beactivated that produces a signal for indicating the presence of theconductive substance.

In one embodiment, for instance, the nonwoven material of the presentdisclosure comprises a nonwoven base web containing pulp fibers in anamount of at least about 50% by weight. The nonwoven base web furthercomprises conductive fibers in an amount of at least 1% by weight, suchas at least 3% by weight. For instance, the conductive fibers may bepresent in the nonwoven base web in an amount sufficient for the baseweb to be conductive in at least one direction and in at least one zone.The conductive fibers incorporated into the base web may comprise, forinstance, carbon fibers, metallic fibers, polymeric fibers containing aconductive material, or mixtures thereof.

In one embodiment, for instance, the nonwoven base web comprises a wetlaid web made according to a tissue making process. The wet laid web,for instance, may comprise a through-air dried web, such as an uncrepedthrough-air dried web.

In one embodiment, it may be desirable to incorporate and concentratethe conductive fibers within a certain layer of the base web. Forinstance, the base web may comprise a single ply web containing distinctlayers of fibers. The base web, for instance, may include at least afirst layer and a second layer. The conductive fibers may all becontained within the second layer.

In one particular embodiment, for instance, the single ply web cancontain a third layer of fibers in addition to the first layer and thesecond layer. The second layer, containing the conductive fibers, may bepositioned in between the first layer and the third layer. The firstlayer and the third layer, for instance, may comprise pulp fibers whilethe second layer may comprise a mixture of the conductive fibers andpulp fibers. In this manner, the base web maintains a soft andnonabrasive feel while containing conductive fibers in an amountsufficient for the base web to conduct electricity.

As described above, in one embodiment, the conductive fibers maycomprise carbon fibers. The carbon fibers, for instance, may be formedfrom polyacrylonitrile. The carbon fibers may comprise chopped fibersthat have a length of from about 1 mm to about 12 mm, such as from about3 mm to about 6 mm. The fibers can have a diameter, for instance, fromabout 3 microns to about 15 microns, such as from about 5 microns toabout 10 microns.

In addition to pulp fibers and conductive fibers, in one embodiment, thebase web can further contain synthetic or polymeric fibers made from athermoplastic material. By incorporating a thermoplastic fiber into thebase web, the base web may be stronger and/or may be amenable to thermalbonding to other components, such as other webs and materials.

Although the nonwoven web described above has many different uses, inone embodiment, the web can be incorporated into an absorbent article.The absorbent article may comprise a chassis having an outer cover, anabsorbent structure, and a liner. The absorbent structure, for instance,may be positioned in between the outer cover and the liner. Dependingupon the article, the chassis may include a crotch region positioned inbetween a front region and a back region. The front region and the backregion may define a waist region therebetween.

In accordance with the present disclosure, the absorbent article canfurther include a wetness sensing device that is activated when aconductive substance is detected in the absorbent article. The wetnesssensing device includes at least one conductive element, such as a pairof spaced apart conductive elements in communication with a signalingdevice. The conductive elements may form an open circuit within theabsorbent article and may be made from a conductive nonwoven webcomprising a mixture of pulp fibers and conductive fibers. When aconductive substance (such as urine) is contacted with the conductiveelements, the open circuit becomes closed causing the signaling deviceto produce a signal indicating the presence of the conductive substance.

The first and second conductive elements contained within the wetnesssensing device may be separate and distinct strips or structures or maybe contained in a single nonwoven web. For instance, in one embodiment,the nonwoven web may include conductive zones that comprise the firstand second conductive elements.

As described, the conductive elements may comprise a wet laid webcontaining pulp fibers combined with carbon fibers. The nonwoven web maycontain the conductive fibers in an amount sufficient so that at leastone zone of the nonwoven web has a resistance of less than about 1500Ohms/Square, such as less than about 100 Ohms/Square, such as less thanabout 30 Ohms/Square, such as less than about 10 Ohms/Square.

Other features and aspects of the present invention are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof to one of ordinary skill in the art, is set forth moreparticularly in the remainder of the specification, including referenceto the accompanying figures in which:

FIG. 1 is a side view of one embodiment of a process for formingmulti-layered webs in accordance with the present disclosure;

FIG. 2 is a side view of one embodiment of a process for forminguncreped through-air dried webs in accordance with the presentdisclosure;

FIG. 3 is a rear perspective view of one embodiment of an absorbentarticle made in accordance with the present disclosure;

FIG. 4 is a front perspective view of the absorbent article illustratedin FIG. 3;

FIG. 5 is a plan view of the absorbent article shown in FIG. 3 with thearticle in an unfastened, unfolded and laid flat condition showing thesurface of the article that faces away from the wearer;

FIG. 6 is a plan view similar to FIG. 5 showing the surface of theabsorbent article that faces the wearer when worn and with portions cutaway to show underlying features;

FIG. 7 is a perspective view of the embodiment shown in FIG. 3 furtherincluding one embodiment of a signaling device; and

FIG. 8 is a perspective view of one embodiment of a conductive nonwovenweb made in accordance with the present disclosure including differentzones of conduction.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the present disclosure.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that thepresent discussion is a description of exemplary embodiments only, andis not intended as limiting the broader aspects of the presentdisclosure.

In general, the present disclosure is generally directed to nonwovenwebs containing conductive fibers. The conductive fibers can beincorporated into the web, for instance, such that the web iselectrically conductive in at least one zone. For instance, the nonwovenweb can be made so that it is capable of carrying an electric current inthe length direction, in the width direction, or in any suitabledirection.

In accordance with the present disclosure, the conductive nonwoven webscan contain a substantial amount of pulp fibers and can be made using atissue making process. For instance, in one embodiment, the conductivefibers can be combined with pulp fibers and water to form an aqueoussuspension of fibers that is then deposited onto a porous surface forforming a conductive tissue web. The conductivity of the tissue web canbe controlled by selecting particular conductive fibers, locating thefibers at particular locations within the web and by controlling variousother factors and variables. In one embodiment, for instance, theconductive fibers incorporated into the nonwoven web comprise choppedcarbon fibers.

Nonwoven webs made in accordance with the present disclosure may be usedin numerous different applications. For instance, in one embodiment, theconductive nonwoven material may be incorporated into any suitableelectronic device. For instance, the nonwoven web can be used as a fuelcell membrane, as a battery electrode, or may be used in printedelectronics. For example, in one particular embodiment, the conductivefibers may form a patterned circuit within the base webs for anysuitable end use application.

In one particular embodiment, for instance, the conductive nonwoven websmade in accordance with the present disclosure may be used to formwetness sensing devices within absorbent articles. The wetness sensingdevice, for instance, may be configured to emit a signal, such as anaudible signal and/or a visible signal, when a conductive substance,such as urine or fecal matter, is detected in the absorbent article. Inone embodiment, for instance, one or more nonwoven webs made inaccordance with the present disclosure can be configured to formconductive elements within an absorbent article for creating an opencircuit that is configured to close when a conductive substance ispresent in the article.

The absorbent article may be, for instance, a diaper, a training pant,an incontinence product, a feminine hygiene product, a medical garment,a bandage, and the like. Generally, the absorbent articles containingthe open circuit are disposable meaning that they are designed to bediscarded after a limited use rather than being laundered or otherwiserestored for reuse.

The open circuit contained within the absorbent articles made fromnonwoven webs of the present disclosure is configured to be attached toa signaling device. The signaling device can provide power to the opencircuit while also including some type of audible and/or visible signalthat indicates to the user the presence of a body fluid. Although theabsorbent article itself is disposable, the signaling device may bereusable from article to article.

As described above, the base webs of the present disclosure are made bycombining conductive fibers with pulp fibers to form nonwoven webs. Inone embodiment, a tissue making process is used to form the webs.

The conductive fibers that may be used in accordance with the presentdisclosure can vary depending upon the particular application and thedesired result. Conductive fibers that may be used to form the nonwovenwebs include carbon fibers, metallic fibers, conductive polymeric fibersincluding fibers made from conductive polymers or polymeric fiberscontaining a conductive material, metal coated fibers, and mixturesthereof. Metallic fibers that may be used include, for instance, copperfibers, aluminum fibers, and the like. Polymeric fibers containing aconductive material include thermoplastic fibers coated with aconductive material or thermoplastic fibers impregnated or blended witha conductive material. For instance, in one embodiment, thermoplasticfibers may be used that are coated with silver.

The conductive fibers incorporated into the nonwoven material can haveany suitable length and diameter. In one embodiment, for instance, theconductive fibers can have an aspect ratio of from about 100:1 to about1,000:1.

The amount of conductive fibers contained in the nonwoven web can varybased on many different factors, such as the type of conductive fiberincorporated into the web and the ultimate end use of the web. Theconductive fibers may be incorporated into the nonwoven web, forinstance, in an amount from about 1% by weight to about 90% by weight,or even greater. For instance, the conductive fibers can be present inthe nonwoven web in an amount from about 3% by weight to about 60% byweight, such as from about 3% by weight to about 20% by weight.

Carbon fibers that may be used in the present disclosure include fibersmade entirely from carbon or fibers containing carbon in amountssufficient so that the fibers are electrically conductive. In oneembodiment, for instance, carbon fibers may be used that are formed froma polyacrylonitrile polymer. In particular, the carbon fibers are formedby heating, oxidizing, and carbonizing polyacrylonitrile polymer fibers.Such fibers typically have high purity and contain relatively highmolecular weight molecules. For instance, the fibers can contain carbonin an amount greater than about 90% by weight, such as in an amountgreater than 93% by weight, such as in an amount greater than about 95%by weight.

In order to form carbon fibers from polyacrylonitrile polymer fibers,the polyacrylonitrile fibers are first heated in an oxygen environment,such as air. While heating, cyano sites within the polyacrylonitrilepolymer form repeat cyclic units of tetrahydropyridine. As heatingcontinues, the polymer begins to oxidate. During oxidation, hydrogen isreleased causing carbon to form aromatic rings.

After oxidation, the fibers are then further heated in an oxygen starvedenvironment. For instance, the fibers can be heated to a temperature ofgreater than about 1300° C., such as greater than 1400° C., such as fromabout 1300° C. to about 1800° C. During heating, the fibers undergocarbonization. During carbonization, adjacent polymer chains jointogether to form a lamellar, basal plane structure of nearly purecarbon.

Polyacrylonitrile-based carbon fibers are available from numerouscommercial sources. For instance, such carbon fibers can be obtainedfrom Toho Tenax America, Inc. of Rockwood, Tenn.

Other raw materials used to make carbon fibers are Rayon and petroleumpitch.

Of particular advantage, the formed carbon fibers can be chopped to anysuitable length. In one embodiment of the present disclosure, forinstance, chopped carbon fibers may be incorporated into the base webhaving a length of from about 1 mm to about 12 mm, such as from about 3mm to about 6 mm. The fibers can have an average diameter of from about3 microns to about 15 microns, such as from about 5 microns to about 10microns. In one embodiment, for instance, the carbon fibers may have alength of about 3 mm and an average diameter of about 7 microns.

In one embodiment, the carbon fibers incorporated into the nonwoven basewebs have a water soluble sizing. Sizing can be in the amount of 0.1-10%by weight. Water soluble sizings, can be, but not limited to, polyamidecompounds, epoxy resin ester and poly(vinyl pyrrolidone). In thismanner, the sizing is dissolved when mixing the carbon fibers in waterto provide a good dispersion of carbon fibers in water prior to formingthe nonwoven web.

In forming conductive nonwoven webs in accordance with the presentdisclosure, the above conductive fibers are combined with other fiberssuitable for use in tissue making processes. The fibers combined withthe conductive fibers may comprise any natural or synthetic cellulosicfibers including, but not limited to nonwoody fibers, such as cotton,abaca, kenaf, sabai grass, flax, esparto grass, straw, jute hemp,bagasse, milkweed floss fibers, and pineapple leaf fibers; and woody orpulp fibers such as those obtained from deciduous and coniferous trees,including softwood fibers, such as northern and southern softwood kraftfibers; hardwood fibers, such as eucalyptus, maple, birch, and aspen.Pulp fibers can be prepared in high-yield or low-yield forms and can bepulped in any known method, including kraft, sulfite, high-yield pulpingmethods and other known pulping methods. Fibers prepared from organosolvpulping methods can also be used, including the fibers and methodsdisclosed in U.S. Pat. No. 4,793,898, issued Dec. 27, 1988 to Laamanenet al.; U.S. Pat. No. 4,594,130, issued Jun. 10, 1986 to Chang et al.;and U.S. Pat. No. 3,585,104. Useful fibers can also be produced byanthraquinone pulping, exemplified by U.S. Pat. No. 5,595,628 issuedJan. 21, 1997, to Gordon et al.

A portion of the fibers, such as up to 50% or less by dry weight, orfrom about 5% to about 30% by dry weight, can be synthetic fibers suchas rayon, polyolefin fibers, polyester fibers, polyvinyl alcohol fibers,bicomponent sheath-core fibers, multi-component binder fibers, and thelike. An exemplary polyethylene fiber is Pulpex®, available fromHercules, Inc. (Wilmington, Del.). Synthetic cellulose fiber typesinclude rayon in all its varieties and other fibers derived from viscoseor chemically-modified cellulose.

Incorporating thermoplastic fibers into the nonwoven web may providevarious advantages and benefits. For example, incorporatingthermoplastic fibers into the web may allow the webs to be thermallybonded to adjacent structures. For instance, the webs may be thermallybonded to other nonwoven materials, such as a diaper liner which maycomprise, for instance, a spunbond web or a meltblown web.

Chemically treated natural cellulosic fibers can also be used such asmercerized pulps, chemically stiffened or crosslinked fibers, orsulfonated fibers. For good mechanical properties in using papermakingfibers, it can be desirable that the fibers be relatively undamaged andlargely unrefined or only lightly refined. Mercerized fibers,regenerated cellulosic fibers, cellulose produced by microbes, rayon,and other cellulosic material or cellulosic derivatives can be used.Suitable fibers can also include recycled fibers, virgin fibers, ormixes thereof. In certain embodiments, the fibers can have a CanadianStandard Freeness of at least 200, more specifically at least 300, morespecifically still at least 400, and most specifically at least 500.

Other papermaking fibers that can be used in the present disclosureinclude paper broke or recycled fibers and high yield fibers. High yieldpulp fibers are those papermaking fibers produced by pulping processesproviding a yield of about 65% or greater, more specifically about 75%or greater, and still more specifically about 75% to about 95%. Yield isthe resulting amount of processed fibers expressed as a percentage ofthe initial wood mass. Such pulping processes include bleachedchemithermomechanical pulp (BCTMP), chemithermomechanical pulp (CTMP),pressure/pressure thermomechanical pulp (PTMP), thermomechanical pulp(TMP), thermomechanical chemical pulp (TMCP), high yield sulfite pulps,and high yield Kraft pulps, all of which leave the resulting fibers withhigh levels of lignin. High yield fibers are well known for theirstiffness in both dry and wet states relative to typical chemicallypulped fibers.

In general, any process capable of forming a tissue web can be utilizedin forming the conductive web. For example, a papermaking process of thepresent disclosure can utilize embossing, wet pressing, air pressing,through-air drying, uncreped through-air drying, hydroentangling, airlaying, as well as other steps known in the art. The tissue web may beformed from a fiber furnish containing pulp fibers in an amount of atleast 50% by weight, such as at least 60% by weight, such as at least70% by weight, such as at least 80% by weight, such as at least 90% byweight.

The nonwoven webs can also be pattern densified or imprinted, such asthe tissue sheets disclosed in any of the following U.S. Pat. No.4,514,345 issued on Apr. 30, 1985, to Johnson et al.; U.S. Pat. No.4,528,239 issued on Jul. 9, 1985, to Trokhan; U.S. Pat. No. 5,098,522issued on Mar. 24, 1992; U.S. Pat. No. 5,260,171 issued on Nov. 9, 1993,to Smurkoski et al.; U.S. Pat. No. 5,275,700 issued on Jan. 4, 1994, toTrokhan; U.S. Pat. No. 5,328,565 issued on Jul. 12, 1994, to Rasch etal.; U.S. Pat. No. 5,334,289 issued on Aug. 2, 1994, to Trokhan et al.;U.S. Pat. No. 5,431,786 issued on Jul. 11, 1995, to Rasch et al.; U.S.Pat. No. 5,496,624 issued on Mar. 5, 1996, to Steltjes, Jr. et al.; U.S.Pat. No. 5,500,277 issued on Mar. 19, 1996, to Trokhan et al.; U.S. Pat.No. 5,514,523 issued on May 7, 1996, to Trokhan et al.; U.S. Pat. No.5,554,467 issued on Sep. 10, 1996, to Trokhan et al.; U.S. Pat. No.5,566,724 issued on Oct. 22, 1996, to Trokhan et al.; U.S. Pat. No.5,624,790 issued on Apr. 29, 1997, to Trokhan et al.; and, U.S. Pat. No.5,628,876 issued on May 13, 1997, to Ayers et al., the disclosures ofwhich are incorporated herein by reference to the extent that they arenon-contradictory herewith. Such imprinted tissue sheets may have anetwork of densified regions that have been imprinted against a drumdryer by an imprinting fabric, and regions that are relatively lessdensified (e.g., “domes” in the tissue sheet) corresponding todeflection conduits in the imprinting fabric, wherein the tissue sheetsuperposed over the deflection conduits was deflected by an air pressuredifferential across the deflection conduit to form a lower-densitypillow-like region or dome in the tissue sheet.

The tissue web can also be formed without a substantial amount of innerfiber-to-fiber bond strength. In this regard, the fiber furnish used toform the base web can be treated with a chemical debonding agent. Thedebonding agent can be added to the fiber slurry during the pulpingprocess or can be added directly to the headbox. Suitable debondingagents that may be used in the present disclosure include cationicdebonding agents such as fatty dialkyl quaternary amine salts, monofatty alkyl tertiary amine salts, primary amine salts, imidazolinequaternary salts, silicone quaternary salt and unsaturated fatty alkylamine salts. Other suitable debonding agents are disclosed in U.S. Pat.No. 5,529,665 to Kaun which is incorporated herein by reference. Inparticular, Kaun discloses the use of cationic silicone compositions asdebonding agents.

In one embodiment, the debonding agent used in the process of thepresent disclosure is an organic quaternary ammonium chloride and,particularly, a silicone-based amine salt of a quaternary ammoniumchloride. For example, the debonding agent can be PROSOFT® TQ1003,marketed by the Hercules Corporation. The debonding agent can be addedto the fiber slurry in an amount of from about 1 kg per metric tonne toabout 10 kg per metric tonne of fibers present within the slurry.

In an alternative embodiment, the debonding agent can be animidazoline-based agent. The imidazoline-based debonding agent can beobtained, for instance, from the Witco Corporation. Theimidazoline-based debonding agent can be added in an amount of between2.0 to about 15 kg per metric tonne.

In one embodiment, the debonding agent can be added to the fiber furnishaccording to a process as disclosed in PCT Application having anInternational Publication No. WO 99/34057 filed on Dec. 17, 1998 or inPCT Published Application having an International Publication No. WO00/66835 filed on Apr. 28, 2000, which are both incorporated herein byreference. In the above publications, a process is disclosed in which achemical additive, such as a debonding agent, is adsorbed ontocellulosic papermaking fibers at high levels. The process includes thesteps of treating a fiber slurry with an excess of the chemicaladditive, allowing sufficient residence time for adsorption to occur,filtering the slurry to remove unadsorbed chemical additives, andredispursing the filtered pulp with fresh water prior to forming anonwoven web.

Wet and dry strength agents may also be applied or incorporated into thebase sheet. As used herein, “wet strength agents” refer to materialsused to immobilize the bonds between fibers in the wet state. Typically,the means by which fibers are held together in paper and tissue productsinvolve hydrogen bonds and sometimes combinations of hydrogen bonds andcovalent and/or ionic bonds. In the present invention, it may be usefulto provide a material that will allow bonding of fibers in such a way asto immobilize the fiber-to-fiber bond points and make them resistant todisruption in the wet state.

Any material that when added to a tissue sheet or sheet results inproviding the tissue sheet with a mean wet geometric tensilestrength:dry geometric tensile strength ratio in excess of about 0.1will, for purposes of the present invention, be termed a wet strengthagent. Typically these materials are termed either as permanent wetstrength agents or as “temporary” wet strength agents. For the purposesof differentiating permanent wet strength agents from temporary wetstrength agents, the permanent wet strength agents will be defined asthose resins which, when incorporated into paper or tissue products,will provide a paper or tissue product that retains more than 50% of itsoriginal wet strength after exposure to water for a period of at leastfive minutes. Temporary wet strength agents are those which show about50% or less than, of their original wet strength after being saturatedwith water for five minutes. Both classes of wet strength agents findapplication in the present invention. The amount of wet strength agentadded to the pulp fibers may be at least about 0.1 dry weight percent,more specifically about 0.2 dry weight percent or greater, and stillmore specifically from about 0.1 to about 3 dry weight percent, based onthe dry weight of the fibers.

Permanent wet strength agents will typically provide a more or lesslong-term wet resilience to the structure of a tissue sheet. Incontrast, the temporary wet strength agents will typically providetissue sheet structures that had low density and high resilience, butwould not provide a structure that had long-term resistance to exposureto water or body fluids.

The temporary wet strength agents may be cationic, nonionic or anionic.Such compounds include PAREZ™ 631 NC and PAREZ® 725 temporary wetstrength resins that are cationic glyoxylated polyacrylamide availablefrom Cytec Industries (West Paterson, N.J.). This and similar resins aredescribed in U.S. Pat. No. 3,556,932, issued on Jan. 19, 1971, to Cosciaet al. and U.S. Pat. No. 3,556,933, issued on Jan. 19, 1971, to Williamset al. Hercobond 1366, manufactured by Hercules, Inc., located atWilmington, Del., is another commercially available cationic glyoxylatedpolyacrylamide that may be used in accordance with the presentinvention. Additional examples of temporary wet strength agents includedialdehyde starches such as Cobond® 1000 from National Starch andChemical Company and other aldehyde containing polymers such as thosedescribed in U.S. Pat. No. 6,224,714, issued on May 1, 2001, toSchroeder et al.; U.S. Pat. No. 6,274,667, issued on Aug. 14, 2001, toShannon et al.; U.S. Pat. No. 6,287,418, issued on Sep. 11, 2001, toSchroeder et al.; and, U.S. Pat. No. 6,365,667, issued on Apr. 2, 2002,to Shannon et al., the disclosures of which are herein incorporated byreference to the extent they are non-contradictory herewith.

Permanent wet strength agents comprising cationic oligomeric orpolymeric resins can be used in the present invention.Polyamide-polyamine-epichlorohydrin type resins such as KYMENE 557H soldby Hercules, Inc., located at Wilmington, Del., are the most widely usedpermanent wet-strength agents and are suitable for use in the presentinvention. Such materials have been described in the following U.S. Pat.No.: 3,700,623, issued on Oct. 24, 1972, to Keim; U.S. Pat. No.3,772,076, issued on Nov. 13, 1973, to Keim; U.S. Pat. No. 3,855,158,issued on Dec. 17, 1974, to Petrovich et al.; U.S. Pat. No. 3,899,388,issued on Aug. 12, 1975, to Petrovich et al.; U.S. Pat. No. 4,129,528,issued on Dec. 12, 1978, to Petrovich et al.; U.S. Pat. No. 4,147,586,issued on Apr. 3, 1979, to Petrovich et al.; and, U.S. Pat. No.4,222,921, issued on Sep. 16, 1980, to van Eenam. Other cationic resinsinclude polyethylenimine resins and aminoplast resins obtained byreaction of formaldehyde with melamine or urea. It can be advantageousto use both permanent and temporary wet strength resins in themanufacture of tissue products.

Dry strength agents are well known in the art and include but are notlimited to modified starches and other polysaccharides such as cationic,amphoteric, and anionic starches and guar and locust bean gums, modifiedpolyacrylamides, carboxymethylcellulose, sugars, polyvinyl alcohol,chitosans, and the like. Such dry strength agents are typically added toa fiber slurry prior to tissue sheet formation or as part of the crepingpackage.

Additional types of chemicals that may be added to the nonwoven webinclude, but is not limited to, absorbency aids usually in the form ofcationic, anionic, or non-ionic surfactants, humectants and plasticizerssuch as low molecular weight polyethylene glycols and polyhydroxycompounds such as glycerin and propylene glycol. Materials that supplyskin health benefits such as mineral oil, aloe extract, vitamin E,silicone, lotions in general and the like may also be incorporated intothe finished products.

In general, the products of the present disclosure can be used inconjunction with any known materials and chemicals that are notantagonistic to its intended use. Examples of such materials include butare not limited to baby powder, baking soda, chelating agents, zeolites,perfumes or other odor-masking agents, cyclodextrin compounds,oxidizers, and the like. Of particular advantage, when carbon fibers areused as the conductive fibers, the carbon fibers also serve as odorabsorbents. Superabsorbent particles, synthetic fibers, or films mayalso be employed. Additional options include dyes, optical brighteners,humectants, emollients, and the like.

Nonwoven webs made in accordance with the present disclosure can includea single homogeneous layer of fibers or may include a stratified orlayered construction. For instance, the nonwoven web ply may include twoor three layers of fibers. Each layer may have a different fibercomposition. For example, referring to FIG. 1, one embodiment of adevice for forming a multi-layered stratified pulp furnish isillustrated. As shown, a three-layered headbox 10 generally includes anupper head box wall 12 and a lower head box wall 14. Headbox 10 furtherincludes a first divider 16 and a second divider 18, which separatethree fiber stock layers.

Each of the fiber layers comprise a dilute aqueous suspension of fibers.The particular fibers contained in each layer generally depends upon theproduct being formed and the desired results. In one embodiment, forinstance, middle layer 20 contains pulp fibers in combination with theconductive fibers. Outer layers 22 and 24, on the other hand, cancontain only pulp fibers, such as softwood fibers and/or hardwoodfibers.

Placing the conductive fibers within the middle layer 20 may providevarious advantages and benefits. Placing the conductive fibers in thecenter of the web, for instance, can produce a conductive material thatstill has a soft feel on its surfaces. Concentrating the fibers in oneof the layers of the web can also improve the conductivity of thematerial without having to add great amounts of the conductive fibers.In one embodiment, for instance, a three-layered web is formed in whicheach layer accounts for from about 15% to about 40% by weight of theweb. The outer layers can be made of only pulp fibers or a combinationof pulp fibers and thermoplastic fibers. The middle layer, on the otherhand, may contain pulp fibers combined with conductive fibers. Theconductive fibers may be contained in the middle layer in an amount fromabout 10% to about 90% by weight, such as in an amount from about 30% toabout 70% by weight, such as in an amount from about 40% to about 60% byweight.

An endless traveling forming fabric 26, suitably supported and driven byrolls 28 and 30, receives the layered papermaking stock issuing fromheadbox 10. Once retained on fabric 26, the layered fiber suspensionpasses water through the fabric as shown by the arrows 32. Water removalis achieved by combinations of gravity, centrifugal force and vacuumsuction depending on the forming configuration.

Forming multi-layered paper webs is also described and disclosed in U.S.Pat. No. 5,129,988 to Farrington, Jr., which is incorporated herein byreference.

Once the aqueous suspension of fibers is formed into a nonwoven web, theweb may be processed using various techniques and methods. For example,referring to FIG. 2, shown is a method for making uncreped, throughdriedtissue sheets. In one embodiment, it may be desirable to form thenonwoven web using an uncreped, through-air drying process. It was foundthat creping the nonwoven web during formation may cause damage to theconductive fibers by destroying the network of conductive fibers withinthe nonwoven web. Thus, the nonwoven web becomes non-conductive.

For simplicity, the various tensioning rolls schematically used todefine the several fabric runs are shown, but not numbered. It will beappreciated that variations from the apparatus and method illustrated inFIG. 2 can be made without departing from the general process. Shown isa twin wire former having a papermaking headbox 34, such as a layeredheadbox, which injects or deposits a stream 36 of an aqueous suspensionof papermaking fibers onto the forming fabric 38 positioned on a formingroll 39. The forming fabric serves to support and carry the newly-formedwet web downstream in the process as the web is partially dewatered to aconsistency of about 10 dry weight percent. Additional dewatering of thewet web can be carried out, such as by vacuum suction, while the wet webis supported by the forming fabric.

The wet web is then transferred from the forming fabric to a transferfabric 40. In one optional embodiment, the transfer fabric can betraveling at a slower speed than the forming fabric in order to impartincreased stretch into the web. This is commonly referred to as a “rush”transfer. The relative speed difference between the two fabrics can befrom 0-15 percent, more specifically from about 0-8 percent. Transfer ispreferably carried out with the assistance of a vacuum shoe 42 such thatthe forming fabric and the transfer fabric simultaneously converge anddiverge at the leading edge of the vacuum slot.

The web is then transferred from the transfer fabric to thethroughdrying fabric 44 with the aid of a vacuum transfer roll 46 or avacuum transfer shoe, optionally again using a fixed gap transfer aspreviously described. The throughdrying fabric can be traveling at aboutthe same speed or a different speed relative to the transfer fabric. Ifdesired, the throughdrying fabric can be run at a slower speed tofurther enhance stretch. Transfer can be carried out with vacuumassistance to ensure deformation of the sheet to conform to thethroughdrying fabric, thus yielding desired bulk and appearance ifdesired. Suitable throughdrying fabrics are described in U.S. Pat. No.5,429,686 issued to Kai F. Chiu et al. and U.S. Pat. No. 5,672,248 toWendt, et al. which are incorporated by reference.

In one embodiment, the throughdrying fabric provides a relatively smoothsurface. Alternatively, the fabric can contain high and long impressionknuckles.

The side of the web contacting the throughdrying fabric is typicallyreferred to as the “fabric side” of the nonwoven web. The fabric side ofthe web, as described above, may have a shape that conforms to thesurface of the throughdrying fabric after the fabric is dried in thethroughdryer. The opposite side of the paper web, on the other hand, istypically referred to as the “air side”. The air side of the web istypically smoother than the fabric side during normal throughdryingprocesses.

The level of vacuum used for the web transfers can be from about 3 toabout 15 inches of mercury (75 to about 380 millimeters of mercury),preferably about 5 inches (125 millimeters) of mercury. The vacuum shoe(negative pressure) can be supplemented or replaced by the use ofpositive pressure from the opposite side of the web to blow the web ontothe next fabric in addition to or as a replacement for sucking it ontothe next fabric with vacuum. Also, a vacuum roll or rolls can be used toreplace the vacuum shoe(s).

While supported by the throughdrying fabric, the web is finally dried toa consistency of about 94 percent or greater by the throughdryer 48 andthereafter transferred to a carrier fabric 50. The dried basesheet 52 istransported to the reel 54 using carrier fabric 50 and an optionalcarrier fabric 56. An optional pressurized turning roll 58 can be usedto facilitate transfer of the web from carrier fabric 50 to fabric 56.Suitable carrier fabrics for this purpose are Albany International 84Mor 94M and Asten 959 or 937, all of which are relatively smooth fabricshaving a fine pattern. Although not shown, reel calendering orsubsequent off-line calendering can be used to improve the smoothnessand softness of the basesheet. Calendering the web may also cause theconductive fibers to orient in a certain plane or in a certaindirection. For instance, in one embodiment, the web can be calendered inorder to cause primarily all of the conductive fibers to lie in the X-Yplane and not in the Z direction. In this manner, the conductivity ofthe web can be improved while also improving the softness of the web.

In one embodiment, the nonwoven web 52 is a web which has been dried ina flat state. For instance, the web can be formed while the web is on asmooth throughdrying fabric. Processes for producing uncrepedthroughdried fabrics are, for instance, disclosed in U.S. Pat. No.5,672,248 to Wendt, et al.; U.S. Pat. No. 5,656,132 to Farrington, etal.; U.S. Pat. No. 6,120,642 to Lindsay and Burazin; U.S. Pat. No.6,096,169 to Hermans. et al.; U.S. Pat. No. 6,197,154 to Chen, et al.;and U.S. Pat. No. 6,143,135 to Hada, et al., all of which are hereinincorporated by reference in their entireties.

In FIG. 2, a process is shown for producing uncreped through-air driedwebs. It should be understood, however, that any suitable process ortechnique that does not use creping may be used to form the conductivenonwoven web.

Nonwoven webs made in accordance with the present disclosure can havevarious different properties and characteristics depending upon theapplication in which the webs are to be used and the desired results.For instance, the nonwoven web can have a basis weight of from about 15gsm to about 200 gsm or greater. For instance, the basis weight of thenonwoven web can be from about 15 gsm to about 100 gsm, such as fromabout 15 gsm to about 50 gsm.

If desired, the nonwoven web can be made with a relatively high bulk.For instance, the bulk can be from about 2 cc/g to about 20 cc/g, suchas from about 3 cc/g to about 10 cc/g.

The sheet “bulk” is calculated as the quotient of the caliper of a drytissue sheet, expressed in microns, divided by the dry basis weight,expressed in grams per square meter. The resulting sheet bulk isexpressed in cubic centimeters per gram. More specifically, the caliperis measured as the total thickness of a stack of ten representativesheets and dividing the total thickness of the stack by ten, where eachsheet within the stack is placed with the same side up. Caliper ismeasured in accordance with TAPPI test method T411 om-89 “Thickness(caliper) of Paper, Paperboard, and Combined Board” with Note 3 forstacked sheets. The micrometer used for carrying out T411 om-89 is anEmveco 200-A Tissue Caliper Tester available from Emveco, Inc., Newberg,Oreg. The micrometer has a load of 2.00 kilo-Pascals (132 grams persquare inch), a pressure foot area of 2500 square millimeters, apressure foot diameter of 56.42 millimeters, a dwell time of 3 secondsand a lowering rate of 0.8 millimeters per second.

The conductivity of the nonwoven web can also vary depending upon thetype of conductive fibers incorporated into the web, the amount ofconductive fibers incorporated into the web, and the manner in which theconductive fibers are positioned, concentrated or oriented in the web.In one embodiment, for instance, the nonwoven web can have a resistanceof less than about 1500 Ohms/square, such as less than about 100Ohms/square, such as less than about 10 Ohms/square.

The conductivity of the sheet is calculated as the quotient of theresistant measurement of a sheet, expressed in Ohms, divided by theratio of the length to the width of the sheet. The resulting resistanceof the sheet is expressed in Ohms per square. More specifically, theresistance measurement is in accordance with ASTM F1896-98 “Test Methodfor Determining the Electrical Resistivity of a Printed ConductiveMaterial”. The resistance measuring device (or Ohm meter) used forcarrying out ASTM F1896-98 is a Fluke multimeter (model 189) equippedwith Fluke alligator clips (model AC120); both are available from FlukeCorporation, Everett, Wash.

The resulting conductive web made in accordance with the presentdisclosure may be used alone as a single ply product or can be combinedwith other webs or films to form a multi-ply product. In one embodiment,the conductive nonwoven web may be combined with other tissue webs toform a 2-ply product or a 3-ply product. The other tissue webs, forinstance, may be made entirely from pulp fibers and can be madeaccording to any of the processes described above.

In an alternative embodiment, the conductive nonwoven web made accordingto the present disclosure may be laminated using an adhesive orotherwise to other nonwoven or polymeric film materials. For instance,in one embodiment, the conductive nonwoven web may be laminated to ameltblown web and/or a spunbond web that are made from polymeric fibers,such as polypropylene fibers. As described above, in one embodiment, theconductive nonwoven web can contain synthetic fibers. In thisembodiment, the nonwoven web may be bonded to an opposing web containingsynthetic fibers such as a meltblown web or spunbond web.

Incorporating the conductive nonwoven web into a multi-ply product mayprovide various advantages and benefits. For instance, the resultingmulti-ply product may have better strength, may be softer, and/or mayhave better liquid wicking properties.

In one embodiment, the conductive fibers may be contained within thenonwoven web so as to form distinct zones of conductivity. For instance,in one embodiment, a head box may be used that instead of or in additionto separating the fibers vertically as shown in FIG. 1, the head box maybe designed to also separate the fibers horizontally. In this manner,conductive fibers may only be contained in certain zones along thelength (machine direction) of the web. The conductive zones may beseparated by non-conductive zones that only contain non-conductivematerials such as pulp fibers.

For instance, as shown in FIG. 8, a conductive nonwoven web 152 made inaccordance with the present disclosure is shown. In this embodiment,conductive zones 266 and 268 have been formed into the web in the lengthdirection. As shown in FIG. 8, the conductive zones 266 and 268 can besurrounded by non-conductive zones 260, 262 and 264.

As described above, nonwoven base webs made in accordance with thepresent disclosure may be used in numerous applications. For instance,the base webs may be used for their ability to conduct electriccurrents. In other embodiments, however, when using carbon fibers, thebase webs may be used for their odor control properties. In still otherembodiments, the conductive fibers may be present at the surface of thenonwoven web providing an abrasive product.

In one particular application, for instance, the conductive nonwoven webmay be incorporated into a wetness sensing device that is configured toindicate the presence of a body fluid within an absorbent article. Thewetness sensing device, for instance, may comprise an open circuit madefrom the conductive nonwoven material. The open circuit can be connectedto a signaling device which is configured to emit an audible, visual orsensory signal when a conductive fluid closes the open circuit.

The particular targeted conductive fluid or body fluid may varydepending upon the particular type of absorbent article and the desiredapplication. For instance, in one embodiment, the absorbent articlecomprises a diaper, a training pant, or the like and the wetness sensingdevice is configured to indicate the presence of urine. Alternatively,the wetness signaling device may be configured to indicate the presenceof a metabolite that would indicate the presence of a diaper rash. Foradult incontinence products and feminine hygiene products, on the otherhand, the wetness signaling device may be configured to indicate thepresence of a yeast or of a particular constituent in urine, such as apolysaccharide.

Referring to FIGS. 3 and 4, for exemplary purposes, an absorbent article120 that may be made in accordance with the present invention is shown.The absorbent article 120 may or may not be disposable. It is understoodthat the present invention is suitable for use with various otherabsorbent articles intended for personal wear, including but not limitedto diapers, training pants, swim pants, feminine hygiene products,incontinence products, medical garments, surgical pads and bandages,other personal care or health care garments, and the like withoutdeparting from the scope of the present invention.

By way of illustration only, various materials and methods forconstructing absorbent articles such as the diaper 120 of the variousaspects of the present invention are disclosed in PCT Patent ApplicationWO 00/37009 published Jun. 29, 2000 by A. Fletcher et al; U.S. Pat. No.4,940,464 issued Jul. 10, 1990 to Van Gompel et al.; U.S. Pat. No.5,766,389 issued Jun. 16, 1998 to Brandon et al., and U.S. Pat. No.6,645,190 issued Nov. 11, 2003 to Olson et al. which are incorporatedherein by reference to the extent they are consistent (i.e., not inconflict) herewith.

A diaper 120 is representatively illustrated in FIG. 3 in a partiallyfastened condition. The diaper 120 shown in FIGS. 3 and 4 is alsorepresented in FIGS. 5 and 6 in an opened and unfolded state.Specifically, FIG. 5 is a plan view illustrating the exterior side ofthe diaper 120, while FIG. 6 illustrates the interior side of the diaper120. As shown in FIGS. 5 and 6, the diaper 120 defines a longitudinaldirection 148 that extends from the front of the article when worn tothe back of the article. Opposite to the longitudinal direction 148 is alateral direction 149.

The diaper 120 defines a pair of longitudinal end regions, otherwisereferred to herein as a front region 122 and a back region 124, and acenter region, otherwise referred to herein as a crotch region 126,extending longitudinally between and interconnecting the front and backregions 122, 124. The diaper 120 also defines an inner surface 128adapted in use (e.g., positioned relative to the other components of thearticle 120) to be disposed toward the wearer, and an outer surface 130opposite the inner surface. The front and back regions 122, 124 arethose portions of the diaper 120, which when worn, wholly or partiallycover or encircle the waist or mid-lower torso of the wearer. The crotchregion 126 generally is that portion of the diaper 120 which, when worn,is positioned between the legs of the wearer and covers the lower torsoand crotch of the wearer. The absorbent article 120 has a pair oflaterally opposite side edges 136 and a pair of longitudinally oppositewaist edges, respectively designated front waist edge 138 and back waistedge 139.

The illustrated diaper 120 includes a chassis 132 that, in thisembodiment, encompasses the front region 122, the back region 124, andthe crotch region 126. Referring to FIGS. 3-6, the chassis 132 includesan outer cover 140 and a bodyside liner 142 (FIGS. 3 and 6) that may bejoined to the outer cover 140 in a superimposed relation therewith byadhesives, ultrasonic bonds, thermal bonds or other conventionaltechniques. Referring to FIG. 6, the liner 142 may suitably be joined tothe outer cover 140 along the perimeter of the chassis 132 to form afront waist seam 162 and a back waist seam 164. As shown in FIG. 6, theliner 142 may suitably be joined to the outer cover 140 to form a pairof side seams 161 in the front region 122 and the back region 124. Theliner 142 can be generally adapted, i.e., positioned relative to theother components of the article 120, to be disposed toward the wearer'sskin during wear of the absorbent article. The chassis 132 may furtherinclude an absorbent structure 144 particularly shown in FIG. 6 disposedbetween the outer cover 140 and the bodyside liner 142 for absorbingliquid body exudates exuded by the wearer, and may further include apair of containment flaps 146 secured to the bodyside liner 142 forinhibiting the lateral flow of body exudates.

The elasticized containment flaps 146 as shown in FIG. 6 define apartially unattached edge which assumes an upright configuration in atleast the crotch region 126 of the diaper 120 to form a seal against thewearer's body. The containment flaps 146 can extend longitudinally alongthe entire length of the chassis 132 or may extend only partially alongthe length of the chassis. Suitable constructions and arrangements forthe containment flaps 146 are generally well known to those skilled inthe art and are described in U.S. Pat. No. 4,704,116 issued Nov. 3, 1987to Enloe, which is incorporated herein by reference.

To further enhance containment and/or absorption of body exudates, thediaper 120 may also suitably include leg elastic members 158 (FIG. 6),as are known to those skilled in the art. The leg elastic members 158can be operatively joined to the outer cover 140 and/or the bodysideliner 142 and positioned in the crotch region 126 of the absorbentarticle 120.

The leg elastic members 158 can be formed of any suitable elasticmaterial. As is well known to those skilled in the art, suitable elasticmaterials include sheets, strands or ribbons of natural rubber,synthetic rubber, or thermoplastic elastomeric polymers. The elasticmaterials can be stretched and adhered to a substrate, adhered to agathered substrate, or adhered to a substrate and then elasticized orshrunk, for example with the application of heat, such that elasticretractive forces are imparted to the substrate. In one particularaspect, for example, the leg elastic members 158 may include a pluralityof dry-spun coalesced multifilament spandex elastomeric threads soldunder the trade name LYCRA and available from Invista, Wilmington, Del.,USA.

In some embodiments, the absorbent article 120 may further include asurge management layer (not shown) which may be optionally locatedadjacent the absorbent structure 144 and attached to various componentsin the article 120 such as the absorbent structure 144 or the bodysideliner 142 by methods known in the art, such as by using an adhesive. Asurge management layer helps to decelerate and diffuse surges or gushesof liquid that may be rapidly introduced into the absorbent structure ofthe article. Desirably, the surge management layer can rapidly acceptand temporarily hold the liquid prior to releasing the liquid into thestorage or retention portions of the absorbent structure. Examples ofsuitable surge management layers are described in U.S. Pat. No.5,486,166; and U.S. Pat. No. 5,490,846. Other suitable surge managementmaterials are described in U.S. Pat. No. 5,820,973. The entiredisclosures of these patents are hereby incorporated by reference hereinto the extent they are consistent (i.e., not in conflict) herewith.

As shown in FIGS. 3-6, the absorbent article 120 further includes a pairof opposing elastic side panels 134 that are attached to the back regionof the chassis 132. As shown particularly in FIGS. 3 and 4, the sidepanels 134 may be stretched around the waist and/or hips of a wearer inorder to secure the garment in place. As shown in FIGS. 5 and 6, theelastic side panels are attached to the chassis along a pair of opposinglongitudinal edges 137. The side panels 134 may be attached or bonded tothe chassis 132 using any suitable bonding technique. For instance, theside panels 134 may be joined to the chassis by adhesives, ultrasonicbonds, thermal bonds, or other conventional techniques.

In an alternative embodiment, the elastic side panels may also beintegrally formed with the chassis 132. For instance, the side panels134 may comprise an extension of the bodyside liner 142, of the outercover 140, or of both the bodyside liner 142 and the outer cover 140.

In the embodiments shown in the figures, the side panels 134 areconnected to the back region of the absorbent article 120 and extendover the front region of the article when securing the article in placeon a user. It should be understood, however, that the side panels 134may alternatively be connected to the front region of the article 120and extend over the back region when the article is donned.

With the absorbent article 120 in the fastened position as partiallyillustrated in FIGS. 3 and 4, the elastic side panels 134 may beconnected by a fastening system 180 to define a 3-dimensional diaperconfiguration having a waist opening 150 and a pair of leg openings 152.The waist opening 150 of the article 120 is defined by the waist edges138 and 139 which encircle the waist of the wearer.

In the embodiments shown in the figures, the side panels are releasablyattachable to the front region 122 of the article 120 by the fasteningsystem. It should be understood, however, that in other embodiments theside panels may be permanently joined to the chassis 132 at each end.The side panels may be permanently bonded together, for instance, whenforming a training pant or absorbent swimwear.

The elastic side panels 134 each have a longitudinal outer edge 168, aleg end edge 170 disposed toward the longitudinal center of the diaper120, and waist end edges 172 disposed toward a longitudinal end of theabsorbent article. The leg end edges 170 of the absorbent article 120may be suitably curved and/or angled relative to the lateral direction149 to provide a better fit around the wearer's legs. However, it isunderstood that only one of the leg end edges 170 may be curved orangled, such as the leg end edge of the back region 124, oralternatively, neither of the leg end edges may be curved or angled,without departing from the scope of the present invention. As shown inFIG. 6, the outer edges 168 are generally parallel to the longitudinaldirection 148 while the waist end edges 172 are generally parallel tothe transverse axis 149. It should be understood, however, that in otherembodiments the outer edges 168 and/or the waist edges 172 may beslanted or curved as desired. Ultimately, the side panels 134 aregenerally aligned with a waist region 190 of the chassis.

The fastening system 180 may include laterally opposite first fasteningcomponents 182 adapted for refastenable engagement to correspondingsecond fastening components 184. In the embodiment shown in the figures,the first fastening component 182 is located on the elastic side panels134, while the second fastening component 184 is located on the frontregion 122 of the chassis 132. In one aspect, a front or outer surfaceof each of the fastening components 182, 184 includes a plurality ofengaging elements. The engaging elements of the first fasteningcomponents 182 are adapted to repeatedly engage and disengagecorresponding engaging elements of the second fastening components 184to releasably secure the article 120 in its three-dimensionalconfiguration.

The fastening components 182, 184 may be any refastenable fastenerssuitable for absorbent articles, such as adhesive fasteners, cohesivefasteners, mechanical fasteners, or the like. In particular aspects thefastening components include mechanical fastening elements for improvedperformance. Suitable mechanical fastening elements can be provided byinterlocking geometric shaped materials, such as hooks, loops, bulbs,mushrooms, arrowheads, balls on stems, male and female matingcomponents, buckles, snaps, or the like.

In the illustrated aspect, the first fastening components 182 includehook fasteners and the second fastening components 184 includecomplementary loop fasteners. Alternatively, the first fasteningcomponents 182 may include loop fasteners and the second fasteningcomponents 184 may be complementary hook fasteners. In another aspect,the fastening components 182, 184 can be interlocking similar surfacefasteners, or adhesive and cohesive fastening elements such as anadhesive fastener and an adhesive-receptive landing zone or material; orthe like. One skilled in the art will recognize that the shape, densityand polymer composition of the hooks and loops may be selected to obtainthe desired level of engagement between the fastening components 182,184. Suitable fastening systems are also disclosed in the previouslyincorporated PCT Patent Application WO 00/37009 published Jun. 29, 2000by A. Fletcher et al. and the previously incorporated U.S. Pat. No.6,645,190 issued Nov. 11, 2003 to Olson et al.

In the embodiment shown in the figures, the fastening components 182 areattached to the side panels 134 along the edges 168. In this embodiment,the fastening components 182 are not elastic or extendable. In otherembodiments, however, the fastening components may be integral with theside panels 134. For example, the fastening components may be directlyattached to the side panels 134 on a surface thereof.

In addition to possibly having elastic side panels, the absorbentarticle 120 may include various waist elastic members for providingelasticity around the waist opening. For example, as shown in thefigures, the absorbent article 120 can include a front waist elasticmember 154 and/or a back waist elastic member 156.

As described above, the present disclosure is particularly directed toincorporating a body fluid indicating system, such as a wetness sensingdevice into the absorbent article 120. In this regard, as shown in FIGS.3-6, the absorbent article 120 includes a first conductive element 200spaced from a second conductive element 202. In this embodiment, theconductive elements extend from the front region 122 of the absorbentarticle to the back region 124 without intersecting. In accordance withthe present disclosure, the conductive elements 200 and 202 can be madefrom a conductive nonwoven material as described above. In theembodiment illustrated in FIG. 4, the conductive elements 200 and 202comprise separate and distinct strips or sheets.

The first conductive element 200 does not intersect the secondconductive element 202 in order to form an open circuit that may beclosed, for instance, when a conductive fluid is positioned in betweenthe conductive elements. In other embodiments, however, the firstconductive element 200 and the second conductive element 202 may beconnected to a sensor within the chassis. The sensor may be used tosense changes in temperature or may be used to sense the presence of aparticular substance, such as a metabolite.

In the embodiment shown in FIG. 3, the conductive elements 200 and 202extend the entire length of the absorbent article 120. It should beunderstood, however, that in other embodiments the conductive elementsmay extend only to the crotch region 126 or may extend to any particularplace in the absorbent article where a body fluid is intended to besensed.

The conductive elements 200 and 202 may be incorporated into the chassis132 at any suitable location as long as the conductive elements arepositioned so as to contact a body fluid that is absorbed by theabsorbent article 120. In this regard, the conductive elements 200 and202 generally lie inside the outer cover 140. In fact, in oneembodiment, the conductive elements 200 and 202 may be attached orlaminated to the inside surface of the outer cover 140 that faces theabsorbent structure 144. Alternatively, however, the conductive elements200 and 202 may be positioned on the absorbent structure 144 orpositioned on the liner 142.

In order for the conductive elements 200 and 202 to be easily connectedto a signaling device, the first conductive element 200 can include afirst conductive pad member 204, while the second conductive element 202can include a second conductive pad member 206. The pad members 204 and206 are provided for making a reliable connection between the opencircuit formed by the conductive elements and a signaling device that isintended to be installed on the chassis by the consumer.

The position of the conductive pad members 204 and 206 on the absorbentarticle 120 can vary depending upon where it is desired to mount thesignaling device. For instance, in FIGS. 3, 5 and 6, the conductive padmembers 204 and 206 are positioned in the front region 122 along thewaist opening of the article. In FIG. 4, on the other hand, theconductive pad members 204 and 206 are positioned in the back region 24along the waist opening of the article. It should be appreciated,however, that in other embodiments, the absorbent article 20 may includeconductive pad members being positioned at each end of each conductiveelement 200 and 202. In this manner, a user can determine whether or notto install the signaling device on the front or the back of the article.In still other embodiments, it should be understood that the pad membersmay be located along the side of the article or towards the crotchregion of the article.

Referring to FIG. 7, for exemplary purposes, a signaling device 210 isshown attached to the conductive pad members 204 and 206. The signalingdevice 210 includes a pair of opposing terminals that are electricallyconnected to the corresponding conductive pad members. When a body fluidis present in the absorbent article 120, the open circuit formed by theconductive elements 200 and 202 is closed which, in turn, activates thesignaling device 210.

The signaling device 210 can emit any suitable signal in order toindicate to the user that the circuit has been closed.

In FIG. 7, the conductive elements 200 and 202 are separate and distinctstrips of material. In other embodiments, however, both of theconductive elements may be contained in a single nonwoven sheet. Forinstance, the conductive elements may be contained in a laminate that isincorporated into the absorbent article. In an alternative embodiment,the conductive elements may comprise conductive zones in a nonwoven web.For example, in one embodiment, the nonwoven material illustrated inFIG. 8 may be incorporated into the absorbent article illustrated inFIG. 3.

EXAMPLE

For exemplary purposes only, the following demonstrates the conductivityof base webs made in accordance with the present disclosure.

Uncreped, through-air dried wetlaid webs were made according to thepresent disclosure containing conductive carbon fibers. The uncreped,through-air drying process used was similar to the processes describedin U.S. Pat. No. 6,887,348, U.S. Pat. No. 6,736,935, U.S. Pat. No.6,953,516, and U.S. Pat. No. 5,129,988 which are all incorporated hereinby reference.

The tissue making process included a three-layer headbox that was usedto form a wet web. More particularly, a three-layered web was producedcontaining northern bleached softwood kraft fibers (LL19 from TerraceBay Pulp Inc.) in the two outer layers and a mixture of the abovesoftwood fibers combined with carbon fibers in the middle layer. Thecarbon fiber used was TENAX 150 fibers obtained from Toho Tenax having acut length of 3 mm. The fiber furnish used to produce the middle layercontained 50% by weight softwood fibers and 50% by weight carbon fibers.The consistency of the stock fed to the headbox was about 0.09 weightpercent.

The three-layered sheet was formed on a twin-wire, suction form rollformer using Lindsay 2164-B and Asten 867a forming fabrics. Thenewly-formed web was dewatered to a consistency of from about 20 toabout 27% using vacuum suction from below the forming fabric beforebeing transferred to a transfer fabric with about 10% rush transfer. Thetransfer fabric used was Appleton Wire T807-1 fabric. A vacuum shoepulling about 6 to about 15 inches of mercury vacuum was used totransfer the web to the transfer fabric.

The web was then transferred to a throughdrying fabric which was also anAppleton Wire T807-1 fabric. The web was carried over the throughdryeroperating at a temperature of about 350° F. (175° C.) and dried to afinal dryness of from about 94 to about 98% consistency.

The resulting web was then tested for resistance. The following resultswere obtained:

Sample 1 Sample 2 Line Speed (FPM) 1400 50 Outer layer 1 35% softwood31% softwood Middle layer 15% carbon fiber 19% carbon fiber 15% softwood19% softwood Outer layer 2 35% softwood 31% softwood Resistance ~26 ~13(Ohms/square)

These and other modifications and variations to the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention, which ismore particularly set forth in the appended claims. In addition, itshould be understood that aspects of the various embodiments may beinterchanged both in whole or in part. Furthermore, those of ordinaryskill in the art will appreciate that the foregoing description is byway of example only, and is not intended to limit the invention sofurther described in such appended claims.

1. A nonwoven material comprising: a nonwoven base web containing pulpfibers in an amount of at least about 50% by weight and having a bulk ofat least about 2 cc/g, the nonwoven base web further comprisingconductive fibers in an amount of at least about 1% by weight, theconductive fibers comprising carbon fibers, metallic fibers, conductivepolymeric fibers, metal coated fibers, or mixtures thereof.
 2. Anonwoven material as defined in claim 1, wherein the nonwoven base webcomprises a wet laid web.
 3. A nonwoven material as defined in claim 1,wherein the conductive fibers comprise carbon fibers.
 4. A nonwovenmaterial as defined in claim 1, wherein the conductive fibers arepresent in the nonwoven base web in an amount sufficient for thematerial to be conductive in at least one direction.
 5. A nonwovenmaterial as defined in claim 1, wherein the base web comprises a singleply web containing distinct layers of fibers, the base web including atleast a first layer and a second layer, the conductive fibers all beingcontained in the second layer.
 6. A nonwoven material as defined inclaim 5, wherein the base web further includes a third layer of fibers,the second layer being positioned in between the first layer and thethird layer.
 7. A nonwoven material as defined in claim 3, wherein thecarbon fibers are formed from a polyacrylonitrile.
 8. A nonwovenmaterial as defined in claim 3, wherein the carbon fibers have anaverage length of from about 1 mm to about 12 mm.
 9. A nonwoven materialas defined in claim 1, wherein the nonwoven base web further containsthermoplastic fibers in addition to pulp fibers and conductive fibers.10. A nonwoven material as defined in claim 1, wherein the conductivefibers are present in the base web such that the base web has multipleconductive zones.
 11. A nonwoven material as defined in claim 10,wherein the conductive zones are separated by nonconductive zones.
 12. Anonwoven material as defined in claim 1, wherein the conductive fibershave an aspect ratio of from about 100:1 to about 1,000:1.
 13. Anonwoven material as defined in claim 2, wherein the base web comprisesan uncreped through-air dried web.
 14. A nonwoven material as defined inclaim 1, wherein the conductive fibers are present in the nonwoven baseweb so as to form at least one conductive zone, the at least oneconductive zone having a resistance of less than about 1500 Ohms/square.15. A nonwoven material as defined in claim 1, wherein the nonwoven baseweb has a basis weight of from about 15 gsm to about 100 gsm.
 16. Anonwoven material as defined in claim 6, wherein the conductive fiberscomprise carbon fibers, the single ply web comprising an uncrepedthrough-air dried web, the first layer and the third layers of the webcomprising pulp fibers, the second layer comprising the carbon fiberscombined with pulp fibers.
 17. A nonwoven material as defined in claim1, wherein the nonwoven material comprises a laminate, the nonwoven baseweb being laminated to at least one other layer of material, the otherlayer of material comprising a woven material, a nonwoven material, or afilm.
 18. A nonwoven material as defined in claim 17, wherein the atleast one other material comprises a nonwoven web containing syntheticfibers.
 19. A nonwoven material comprising: a nonwoven base webcomprising a single ply web containing layers of fibers, the base webincluding at least a first layer of fibers and a second layer of fibers,the first layer containing pulp fibers, the second layer containingconductive fibers.
 20. A nonwoven material as defined in claim 19,wherein the second layer contains pulp fibers combined with theconductive fibers, the conductive fibers being present in the base webin an amount of at least about 1% by weight.
 21. A nonwoven material asdefined in claim 19, wherein the conductive fibers comprise carbonfibers.
 22. A nonwoven material as defined in claim 19, wherein the baseweb further includes a third layer of fibers, the second layer beingpositioned in between the first layer and the third layer, the firstlayer and the third layer comprising essentially pulp fibers.
 23. Anonwoven material as defined in claim 22, wherein the second layercontains conductive fibers combined with pulp fibers, the conductivefibers comprising carbon fibers, the carbon fibers being present in thesecond layer in an amount from about 5% to about 90% by weight.
 24. Anonwoven material as defined in claim 23, wherein the conductive fibersare present in the nonwoven base web so as to form at least oneconductive zone, the at least one conductive zone having a resistance ofless than about 1500 Ohms/square.
 25. A nonwoven material as defined inclaim 24, wherein the carbon fibers have an average length of from about1 mm to about 12 mm.
 26. A nonwoven material as defined in claim 23,wherein the conductive fibers are present in the base web such that thebase web has multiple conductive zones.
 27. A nonwoven material asdefined in claim 26, wherein the conductive zones are separated bynonconductive zones.
 28. A nonwoven material as defined in claim 23,wherein the base web comprises an uncreped through-air dried web.